Automotive milling machine, as well as method for discharging milled material

ABSTRACT

In an automotive milling machine, comprising a machine frame, comprising a controller for the travelling and milling operation, comprising a working drum, comprising a transport conveyor for discharging the milled material milled off by the working drum onto a loading surface of a transport vehicle comprising a rear wall, where the transport conveyor is slewable, relative to the machine frame, about a first axis extending essentially horizontally under an elevation angle, and sideways about a second axis extending orthogonally to the first axis under a slewing angle, it is provided for the following features to be achieved: a detection device is arranged on the bottom side of the transport conveyor, where said detection device is used to initiate an activation signal in case of the transport conveyor approaching an object, in particular, the rear wall of the loading surface.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to an automotive milling machine, a method fordischarging milled material, as well as a road or ground working unit.

2. Description of the Prior Art

With an automotive milling machine, it is known to discharge the milledmaterial onto no less than one transport vehicle comprising a loadingsurface.

The milling machine comprises a controller for the travelling andmilling operation, as well as a working drum for the milling of, forexample, a road pavement. A transport conveyor device, for example, atransport conveyor device comprising no less than one transportconveyor, is present in front of or behind the working drum as seen inthe direction of travel. The transport conveyor device comprises adischarge end at which the milled material is discharged onto theloading surface of the no less than one transport vehicle via a flightpath in the form of a parabolic trajectory attributable to the conveyingspeed. The last or single transport conveyor of the transport conveyordevice as seen in the direction of transport may be slewed sideways,relative to the longitudinal axis of the milling machine, under aspecifiable slewing angle to the left or right and may be adjustable inheight via a specifiable elevation angle. In addition, the conveyingspeed of the transport conveyor may be adjustable.

In practical operation, problems arise in coordinating the millingmachine with the transport vehicle.

With a forward-loading milling machine, for example, the milled materialis discharged towards the front onto the transport vehicle drivingahead. The operator of the milling machine needs to signal to thevehicle driver of the transport vehicle as to when the transport vehicleis to continue moving forward and when it is to stop. This leads toproblems because the operator basically needs to concentrate on themilling process and at the same time needs to avoid a collision with thetransport vehicle driving ahead. The information is usually communicatedby means of sounding a horn so that, as soon as the vehicle driver ofthe transport vehicle hears the horn sounding, the transport vehicle ismoved forward by a certain distance. In this context, a problem arisesin the situation where the vehicle driver of the transport vehicle failsto hear the horn alert or if another vehicle driving past emits a hornalert. DE 10 2009 041 842 A (U.S. Pat. No. 8,979,424) addresses theseproblems. The following problems may arise: If the vehicle driver failsto hear the horn alert, and if the same does not drive the transportvehicle forward, this may cause a collision of the slewable transportconveyor of the transport conveyor device with the transport vehicle, orthe operator of the milling machine needs to stop the continuous millingprocess.

If another vehicle driving past emits a horn alert, the vehicle driverof the transport vehicle may erroneously be of the opinion that he hasto stop his vehicle. In this case, there is also the risk of collision.

An additional problem lies in the fact that the operator of the millingmachine also needs to deal with loading the loading surface by adjustingthe slewing angle, elevation angle and conveying speed of the last orsingle transport conveyor of the transport conveyor device as seen inthe direction of transport and is thus distracted from his actual taskof carrying out the milling operation. A correction of the slewing anglemay be required, for example, when altering the steering direction ofthe milling machine.

In case of a rearward-loading milling machine, problems also arise incoordinating the milling machine with the transport vehicle especiallyas the transport vehicle needs to drive behind the milling machine inreverse travel. An even higher level of stress results for the operatorof the milling machine as he needs to control the milling process inforward travel on the one hand, and needs to monitor loading of thetransport vehicle behind the milling machine as seen in the direction oftravel, needs to control the slewing angle, elevation angle and/orconveying speed of the transport conveyor device, and needs tocommunicate the necessary information to the vehicle driver on theother.

It is generally known to measure the distance between the millingmachine and the transport vehicle by means of ultrasonic measuringsystems or other distance measuring systems in order to avoid collisionsbetween the milling machine and the transport vehicle. It is a problemin this context that the different transport vehicles do not have auniform reference surface which the distance measurement could refer to.A different height of the rear wall of the transport vehicles and adifferent incline of the transport conveyor, in conjunction withdifferent slewing angles of the transport conveyor, lead to collisionsof the transport conveyor with the rear wall at entirely differentdistances between the milling machine and the transport vehicle.Basically, there is the problem that a sensor can only be aligned tonon-clearly defined reference surfaces of different transport vehicleswith considerable difficulty. Further problems exist if the transportvehicle is not aligned rectilinearly with the milling machine, or thetransport container of the transport vehicle exhibits a slanting or, inany case, non-vertical rear wall. Distance measuring systems fail inparticular if the transport vehicle is moved at a lateral offset to themilling machine and the transport conveyor can collide with a corner ofthe container.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to specify an automotivemilling machine as well as a method for discharging milled material of amilling machine which, in all operating situations, prevent damages tothe milling machine during the coordination of the discharging process.

The invention advantageously specifies for a detection device to bearranged on the bottom side of the transport conveyor, where saiddetection device is used to initiate an activation signal in case of thetransport conveyor approaching an object, in particular, the rear wallof the loading surface.

A collision with the container of the transport vehicle is safelyprevented by means of the detection device arranged on the bottom sideof the transport conveyor, irrespective of the elevation angle orslewing angle of the transport conveyor adjusted, irrespective of therelative angular position of the transport vehicle to the millingmachine, and irrespective of the shape of the container at the rear walland of the height of the rear wall of the container. The detectiondevice offers the specific advantage of being independent of themovements of the transport vehicle and milling machine relative to oneanother.

It is preferably specified for the detection device to comprise no lessthan one planar-shaped or no less than one linear-shaped sensingelement. Such sensing element is able to detect, on the bottom side ofthe transport conveyor over an extended section underneath the transportconveyor, contact with an object early and irrespective of the slewingposition of the transport conveyor.

It is preferably specified for the sensing element to extendsymmetrically to a longitudinal centre line of the transport conveyorand/or to extend at an essentially parallel distance to the transportconveyor. This enables a collision to be detected early without thetransport conveyor, on the bottom side, and/or the collision objectbeing damaged.

The sensing element may be flexible and may be comprised of a pull ropeor of a flexible surface structure and extends linearly. The flexiblesensing element may also be deflectable in order to maintain anessentially uniform distance to the bottom side of the transportconveyor and for adaptation to a curved shape of the transport conveyor.

Alternatively, the sensing element is rigid and is comprised of, forexample, a rectangular-shaped plate element.

In case of contact with the rear wall of a loading surface or anotherobject, the flexible or rigid sensing element of the detection deviceacts on the sensor which generates the activation signal and transmitsit to the controller.

With a flexible sensing element, a tensile force may be detected at theends of the element which arises through the displacement of the sensingelement. A rigid sensing element may, for example, be attached to thetransport conveyor in a parallelogram-type fashion so that thedisplacement of the suspension can be detected by the sensor.

A preferred embodiment specifies for the controller, in the presence ofan activation signal, to generate a control signal for the reduction ofthe advance speed or for machine stoppage, and/or to increase theelevation angle of the transport conveyor, and/or to generate a drivesignal for the vehicle driver of the transport vehicle.

It may alternatively or additionally be specified for the controller, inthe presence of an activation signal, to generate an alarm signal and/ora signal for the reduction of the conveyor belt speed.

Reducing the conveyor belt speed serves to ensure that no milledmaterial is discharged onto the roof of the driver's cabin of thetransport vehicle by shortening the parabolic trajectory of the milledmaterial.

The sensing element may be coupled to no less than one mechanicallyoperatable or capacitive or inductive or optoelectronic sensor.

Alternatively, the sensing element may be formed of multiple capacitiveor inductive or optoelectronic sensors arranged in a linearly orplanarly distributed fashion.

According to a further alternative, the sensing element may be formed ofno less than one light barrier.

It is possible to generate a locomotion control signal, for example, avisual or an audible signal, in accordance with the activation signal.Locomotion control signals for the transport vehicle have been generallydescribed in DE 10 2009 041 842 A1.

The method according to the invention specifies for a detection deviceto be used on the bottom side of the transport conveyor, said detectiondevice being used to generate an activation signal in the event of thetransport conveyor approaching an object, in particular, the rear wallof the loading surface.

A preferred embodiment specifies for the controller to comprise adetection and control unit which automatically controls positioning of apoint of impingement of the milled material.

Such controller enables the operator of the milling machine toconcentrate on the milling operation and on travelling along a specifiedmilling track. An automatic discharging procedure is thus realized whichensures automatic coordination of the discharging procedure with themovement of the milling machine and of the transport vehicle even whencornering. For example, the slewing angle of the last or singletransport conveyor of the transport conveyor device as seen in thedirection of transport may also be controllable in accordance with thesteering angle of the automotive milling machine.

Hereinafter, embodiments of the invention are illustrated in more detailwith reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is shown:

FIG. 1 a forward-loading road milling machine,

FIG. 2 a rearward-loading road milling machine,

FIG. 3 a top view of a milling machine according to FIG. 1,

FIG. 4 a further embodiment,

FIG. 5 a view of the bottom side of the transport conveyor according toFIG. 1,

FIG. 6 an alternative embodiment,

FIG. 7 a further embodiment with sensors arranged in a planar fashion,and

FIG. 8 an embodiment comprising a light barrier.

DETAILED DESCRIPTION

FIG. 1 shows a milling machine 1 using as an example a forward-loadingroad milling machine 1 a. Said milling machine 1 comprises a machineframe 2 which is supported by a chassis 4 comprised of, for example,tracked ground-engaging units or wheels, said chassis 4 being connectedto the machine frame 2 via no less than three height adjustment devicesin the design of lifting columns 5. As can be inferred from FIG. 2, theembodiment specifies four lifting columns 5 which can be used to bringthe machine frame 2 into a specifiable plane extending preferablyparallel to the road surface 6 which supports the trackedground-engaging units of the chassis 4.

The road milling machine shown in FIG. 1 comprises, in longitudinaldirection of the milling machine 1 a, a working drum 22 between thetracked ground-engaging units of the chassis 4.

The milling machines 1 a, 1 b may comprise tracked ground-engaging unitsand/or wheels. The working drum may be adjustable in height via thelifting columns 5 supporting the machine frame 2 or relative to themachine frame 2.

Other designs of a milling machine 1 b may also exhibit the working drum22, for example, at the height of the rear tracked ground-engaging unitsor wheels of the chassis 4.

The transport conveyor device with no less than one transport conveyor11, 12 for transporting away the milled-off milled material may also bearranged at the front end 7 or rear end 8 of the milling machine 1 a, 1b.

FIG. 2 shows a rearward-loading milling machine 1 b as an example inwhich the transport vehicle 10 drives behind the milling machine 1 inreverse travel.

Provided that sufficient space is available on the side next to themilling machine 1 a, 1 b, the transport vehicle 10 may also be moved inforward travel in front of the milling machine 1 on a different track asshown in FIG. 3.

The directions of travel of the respective vehicles in FIGS. 1 to 3 areindicated by arrows.

In the embodiment shown in FIG. 1, the milled material milled off by theworking drum 22 is discharged onto the loading surface 15 of thetransport vehicle 10 via a first permanently installed transportconveyor 11 of the transport conveyor device which transfers the milledmaterial 14 onto a second slewable transport conveyor 12. As a result ofthe speed of the transport conveyor 12, the milled material 14 is notdischarged immediately at the end of the transport conveyor 12, but themilled material follows a parabolic trajectory so that the point ofimpingement 16 on the loading surface 15 is present at a distance fromthe free end 13 of the transport conveyor 12. The transport conveyor 12is slewable from a neutral position to the left or to the right viapiston-cylinder units 18 in order to be able to discharge the milledmaterial 14 onto the loading surface 15 even when cornering or in theevent of the transport vehicle 10 driving in an offset track. Inaddition, the vehicle driver of the milling machine 1 a, 1 b can adjustthe elevation angle of the transport conveyor 12 by means of apiston-cylinder unit 20. The elevation angle has an influence on theparabolic trajectory of the milled material 14 and on the position ofthe point of impingement 16, as has the conveying speed of the transportconveyor 12.

The currently adjusted elevation angle about a horizontal first axis 21or slewing angle about a vertical second axis 23, respectively, isreported to a detection and control unit 24 further comprising no lessthan one detector 26 which continuously detects the position of theloading surface 15 and/or of the last or single transport conveyor 12 asseen in the direction of transport. Said detector 26 is arrangeableeither at the milling machine 1 a, 1 b, at the end facing the transportconveyor device, or at the free end 13 of the transport conveyor 12.

The detection and control unit 24 is capable of being integrated intothe controller 3 for the travelling and milling operation or, as aminimum, is connectable to the same in order to, should the need arise,also obtain data on the travel speed and/or a detected steering angle ofthe milling machine 1 a, 1 b and the conveying speed of the transportconveyor 12.

FIGS. 1 and 2 show a detection device 50 on the bottom side of thetransport conveyor 12, said detection device 50 comprising alinear-shaped sensing element 52. The sensing element 52 may becomprised of, for example, no less than one rope-type or wire-typeelement which extends essentially parallel and at a distance to thetransport conveyor 12 and is clamped at the ends of the same in such afashion that no less than one sensor 56 can detect a displacement of thesensing device 52.

The sensing element 52 extends preferably symmetrically to alongitudinal centre line 40 of the transport conveyor 12, as can best beinferred from FIGS. 5 and 6. The sensing element 52 may, for example, beformed of wire ropes (FIG. 6) or of a flexible surface structure whichis fastened similar to the linear-shaped sensing element in such afashion that a displacement of the surface structure when in contactwith an object or with the rear wall 60 of the transport vehicle 10initiates, via no less than one sensor 56, an activation signal which isfeedable to the controller 3.

The sensing element may also be comprised of a rigid plate element whichis attached at the transport conveyor 12 in a parallelogram-type fashionas shown in FIGS. 4 and 5. In this arrangement, the sensors 56 may bedesigned, for example, as rotary angle sensors which, at the joints, candetect a movement of the suspension 54. It is understood that theplate-shaped sensing element 52 can be retained in its unloadedposition, for example, by means of spring force, and is displaced onlyin the event of contact with an object.

The sensing elements 52 may each be coupled to no less than onemechanically operatable sensor or to a capacitive or inductive oroptoelectronic sensor.

According to an alternative illustrated in FIG. 7, the detection device50 may, in the areas of the flexible or rigid sensing elements 52inferable from FIGS. 1 to 6, be formed of multiple capacitive orinductive or optoelectronic sensors 58 arranged in a linearly orplanarly distributed fashion.

According to a further alternative shown in FIG. 8, the detection device50 may be formed, for example, in the areas of the flexible or rigidsensing elements 52 inferable from FIGS. 1 to 6, of no less than onelight barrier 54.

The longitudinal extension of the detection device 50 may essentiallyextend over the major part of the length of the transport conveyor 12,as is shown in FIG. 1, or may extend to a partial area being of interestonly, as is illustrated in FIGS. 2 and 4.

The detection and control unit 24 can locate the alterable position ofthe loading surface 15 of the transport vehicle 10 and of the transportconveyor 12 relative to the machine frame 2, and continuously andautomatically control positioning of the point of impingement 16 of themilled material 14 via the slewing angle and/or the elevation angleand/or the conveying speed of the transport conveyor device so that thedischarged milled material 14 impinges, as a minimum, within the loadingsurface 15. Alternatively, the alterable position of the loading surface15 of the transport vehicle 10 may also be continuously located relativeto the transport conveyor 12 in order to perform the control operation.

The invention claimed is:
 1. An automotive milling machine for millingoff milled material and discharging the milled material onto a loadingsurface of a transport vehicle, the milling machine comprising: amachine frame; a working drum supported from the machine frame formilling off the milled material; a transport conveyor arranged toreceive the milled material milled off by the working drum and todischarge the milled material onto the loading surface of the transportvehicle, the transport conveyor being mounted on the machine frame to bepivotable relative to the machine frame about an essentially horizontalfirst axis to define an elevation angle, and the transport conveyorbeing pivotable sideways about a second axis extending orthogonally tothe first axis to define a slewing angle, the transport conveyorincluding a bottom side; a detector comprising a sensing element havingfirst and second ends respectively coupled to first and second endpositions along the bottom side of the transport conveyor and configuredto initiate an activation signal in case of contact by the sensingelement with an object; and a controller connected to the detector andconfigured, responsive to the activation signal from the detector, togenerate one or more collision avoidance signals.
 2. The automotivemilling machine of claim 1, wherein the sensing element comprises atleast one planar-shaped sensing element.
 3. The automotive millingmachine of claim 1, wherein the sensing element comprises at least onelinear-shaped sensing element.
 4. The automotive milling machine ofclaim 1, wherein the sensing element extends symmetrically to alongitudinal center line of the transport conveyor.
 5. The automotivemilling machine of claim 1, wherein the sensing element extendsessentially parallel to the transport conveyor at a distance from thetransport conveyor.
 6. The automotive milling machine of claim 1,wherein the detector further comprises a sensor, and in case of contactof the sensing element with the object, the sensing element acts on thesensor and the sensor generates the activation signal.
 7. The automotivemilling machine of claim 1, wherein the one or more collision avoidancesignals comprise a control signal in response to the activation signalfrom the detector, and wherein the control signal is configured toreduce an advance speed of the milling machine and/or increase theelevation angle of the transport conveyor.
 8. The automotive millingmachine of claim 1, wherein the one or more collision avoidance signalscomprise a control signal in response to the activation signal from thedetector, and wherein the control signal is configured as a drive signalfor a vehicle driver of the transport vehicle.
 9. The automotive millingmachine of claim 1, wherein the one or more collision avoidance signalscomprise an alarm signal in response to the activation signal from thedetector.
 10. The automotive milling machine of claim 1, wherein the oneor more collision avoidance signals comprise a signal for a reduction ofa conveyor belt speed in response to the activation signal from thedetector.
 11. An automotive milling machine for milling off milledmaterial and discharging the milled material onto a loading surface of atransport vehicle, the milling machine comprising: a machine frame; aworking drum supported from the machine frame for milling off the milledmaterial; a transport conveyor arranged to receive the milled materialmilled off by the working drum and to discharge the milled material ontothe loading surface of the transport vehicle, the transport conveyorbeing mounted on the machine frame to be pivotable relative to themachine frame about an essentially horizontal first axis to define anelevation angle, and the transport conveyor being pivotable sidewaysabout a second axis extending orthogonally to the first axis to define aslewing angle, the transport conveyor including a bottom side; a firstdetector configured to detect one or more of a position of the loadingsurface and a position of the conveyor as seen in the direction oftransport; a second detector comprising a sensing element having firstand second ends respectively coupled to first and second end positionsalong the bottom side of the transport conveyor and configured toinitiate an activation signal in case of the transport conveyorapproaching an object; and a controller connected to the first detectorand the second detector and configured, responsive to the activationsignal from the second detector, to generate one or more collisionavoidance signals.
 12. The automotive milling machine of claim 11,wherein the second detector comprises: at least one sensor coupled tothe sensing element, the sensor being selected from the group consistingof a mechanically operable sensor, a capacitive sensor, an inductivesensor, and an optoelectronic sensor.
 13. The automotive milling machineof claim 11, wherein the second detector comprises a plurality oflinearly distributed sensing elements.
 14. The automotive millingmachine of claim 11, wherein the second detector comprises a pluralityof planarly distributed sensing elements.
 15. The automotive millingmachine of claim 11, wherein the second detector comprises at least onelight barrier.
 16. The automotive milling machine of claim 11, whereinthe one or more collision avoidance signals comprise a control signal inresponse to the activation signal from the second detector, and whereinthe control signal is configured to reduce an advance speed of themilling machine and/or increase the elevation angle of the transportconveyor.
 17. The automotive milling machine of claim 11, wherein theone or more collision avoidance signals comprise a control signal inresponse to the activation signal from the second detector, and whereinthe control signal is configured as a drive signal for a vehicle driverof the transport vehicle.
 18. The automotive milling machine of claim11, wherein the one or more collision avoidance signals comprise analarm signal in response to the activation signal from the seconddetector.
 19. The automotive milling machine of claim 11, wherein theone or more collision avoidance signals comprise a signal for areduction of a conveyor belt speed in response to the activation signalfrom the second detector.